Atwell is London-born and has performed on stage and screen. She was in the 2009 West End production "A View from a Bridge." She's not completely new to film, either, having made her big-screen debut in the 2007 Woody Allen movie "Cassandra's Dream." She also appeared in the period film "The Duchess."

The brown-haired beauty has received acclaim for her role as Peggy Carter, Captain America's commanding officer and love interest. Screen Crave called her performance "excellent" and adds, "She's also incredibly charming."

The 29-year-old admits she was incredibly hands-on for her "Captain America" role: The actress improvised a natural reaction to reach out and touch Chris Evans's chest after he's transformed from shrimp to super-soldier. She told PopSugar, "That was an instinctive moment. I literally couldn't help myself, because I hadn't seen him with his top off until that moment." Director Joe Johnston loved it. He told the star, "Do that again."

Evans's wasn't the only buff bod on set: The actress trained for two and a half months before the shoot and throughout the five months of filming to physically look the part. She told the Hollywood Reporter, "It was very important, in playing Peggy, that you could tell she had strength and that she could hold a machine gun."